Record numbers of right whales this spring in Cape Cod Bay

A record 39 northern right whales were born this winter off the coast of Georgia and northern Florida. The whales migrate to Cape Cod Bay in spring.

Rich Eldred

Call it a big baby boom of very big (3,000-pound) babies.

According to Amy Knowlton, research scientist at the New England Aquarium, a record 39 northern right whales were born this winter off the coast of Georgia and northern Florida. Considering there were only about 400 in the world, that’s a nice little population boost.

“As I recall, that’s triple the average rate of births in the past,” said Charles “Stormy” Mayo, director of Right Whale Habitat Studies at Provincetown Center for Coastal Studies.

But right whales, which are now feeding in big (from 50 to 60) numbers in Cape Cod Bay, remain deeply imperiled.

“The struggle for right whales to survive in the future is not dependent on one year up or one year down,” Mayo said. “What whales need are long-term stable conditions. So we take the positive numbers we had this year and celebrate them but the situation with the right whale is bad. If we’d had a bad year, we might have said it’s grave but this year has been a good one.”

New England Aquarium maintains the whale photo database and keeps track of population demographics. The individuals are identifiable by calluses on the head.

The previous high for births was 31 in 2001.

Life is hazardous for right whales in general, especially when they’re young, even when they’re 15 feet long and weigh a ton and a half.

“They do get struck by ships disproportionately,” said Mayo. “The success of the calves will be measured by how many make it into the reproductive pool many years hence. So everything is slow motion, both success and collapse.”

Right whales were hunted from the 11th to 19th centuries and have been protected since 1937. They can live a long time. Knowlton said one whale first seen in 1935 was spotted in 1995; unfortunately with fatal injuries, but that gives it a lifespan of at least 70 years.

But the number of reproductive-age females is only around 80, which limits genetic diversity and if they get too old to breed – could limit it to zero. That’s why the recruitment of young whales is critical.

“With only 400 whales, there’s a long way to go before the population is healthy. It’ll take generations to see the population recover,” Knowlton said.

On average, right whales need to be 9 years old before they can reproduce. “A lot of females give birth and go into a resting phase. The interval between calves can be as low as three years. And they give birth to only one calf,” Mayo pointed out. “My guess is there won’t be anything like that reproduction next year.”

Earlier arrival

They don’t eat when they’re down off Georgia. The moms and calves should be on their way north to feed on delicious copepods.

“The food of the Gulf of Maine is what supports the mothers having calves,” Mayo noted. “I expect we’ll see calves in the very near future. I used to say the first week of April we’d see the first calves. In the past there were several occasions when the bay in late season looked like a nursery ground.”

The right whales arrived earlier than usual this year; the first one spotted in January. Now the bay is hopping with them.

“Over the last few weeks an intense aggregation of whales has been feeding in the bay. We’ve had as many as 50 or 60 animals in the bay,” Mayo marveled.

The center counts them from the air, with flights twice a week from January to mid-May. They fly out of Chatham before 10 a.m.

“That gives us more daylight hours,” explained Ruth Leeney, director of the aerial survey. “We have days when we end up flying for eight hours. When you have 60 whales and you’re taking photos of every individual, you can end up doing a lot of circles. If we don’t see any whales, it takes four hours.”

They circle over the whale to take photos. The pilot and co-pilot spot the whales and two center team members photograph and record GPS, behavior and other data.

“Cape Cod Bay is an ideal research lab,” said Leeney. “It’s a place where a large percentage of the population hangs around for a significant portion of time.”

You don’t have to be in an airplane to see the whales.

“Off Race Point they come close to shore. At Provincetown last year at Herring Cove in April you could watch right whales 40 feet away [while you were] standing on the beach,” Leeney said. “We see them often from the beach in Truro. You see the blow and the tails when they do a dive.”

The young calves should arrive in a week or two.

“Boats go out once a week to survey food resources,” said Mayo.

Linking whales to available food resources could help predict movements and help avoid ship strikes, a large cause of mortality, or entanglements with fishing gear.

“Cape Cod Bay is one of the real active areas for right whale conservation and one of the most active inshore areas where one of the world’s rarest on earth comes. It has supplied them for millennia,” Mayo said.

It is supplying them with two food sources; species of Pseudocalanus drift in early in the season. Later there is a second wave of Calanus finmarchicus. The two copepods are only about 1 to 2 millimeters in size but are abundant enough that one patch last April covered 111.2 square kilometers of the bay.

The calanus hasn’t arrived yet andwhen it does, Mayo hopes it keeps the whales around another month.

The whales are benefiting from new ship strike rules that slow traffic or reroute it when whales are in the area.

“They are very important advances but they are not the ultimate complete solution for sure. It will be extremely difficult to measure how much impact these rules have had,” Mayo said. “Ship strikes are rare events. The actual number that happens is quite low. So if this year it’s two and next year it’s none, is it a trend or is it just chance?”

But the number does seem to be down. The flights have also rescued entangled whales.

“When we have an entangled right whale in the bay, we can spot them easier than someone on the surface,” Leeney said. “Last year, 14 percent of all our flight hours were assisting with entanglements.”

North Atlantic right whale

Adult weight: Up to 80 tons

Adult length: Up to 55 feet

Lifespan: 70 to 100 years or more

Range: North Atlantic, usually Nova Scotia to southeastern Florida; occasional sightings in Iceland and Norway

Diet: Zooplankton, copepods

Where to view: From Race Point Beach, Herring Cove Beach, Provincetown